SharePoint 2007 is an older version of a document sharing website. The newer version, SharePoint 2013, has been integrated with Office 365 and can be found in the Outlook Web App. You can log in here if your school or business has a subscription.
So why is SharePoint 2007 (SP07) getting switched to SharePoint 2013 (SP13)? The platform of SP07 is getting out of date, and is unable to host some newer versions of other Microsoft documents. Because of this, Central IT has decided to switch the content over from SP07 to SP13. Everything will either be retained and switched to SP13 or will be archived, depending on what the owners of each site decide they would like.